Modular timepieces are known. Although very widely known in electronic horology, they are less frequent in mechanical horology, where modular construction, generally devised to break down the same basic mechanical movement into several calibres with different functions or having a different appearance, is usually more expensive than the traditional method of manufacture. Only a few additional mechanisms, made on additional plates, are relatively widespread.
Modular construction conventionally imposes the constraint of machining high precision interfaces, because of the accumulation of assembly clearances between modules, which require very tight tolerances for each module, to ensure a satisfactory result for the entire unit.
Modular manufacture is also very often detrimental to the total thickness of the mechanical movement, and it is difficult to make ultra flat or even simply flat mechanical movements.
However, modular construction remains an interesting objective for timepiece manufacturers, since it allows assembling tasks to be split. In return for the tighter manufacturing tolerances required by the accumulation of clearances between modules, the final assembly operation can be carried out by less skilled personnel because it is less complicated. However, the final assembly operation still requires the knowledge and sensitivity of a watchmaker.
EP Patent Application No. 1 079 284 in the name of ETA discloses a watch with two main modules each of which contains half of the components.
EP Patent Application No. 0 862 098 in the name of VOSS discloses a modular watch with a timing mechanism forming an entire module.
EP Patent Application No 1 211 578 in the name of ETA discloses an ultra thin electromechanical movement with stacked modules, implementing tubular elements compensating for the variations in thickness of the assembly elements.